10 



b. The Heart and Blood. 



(a) Examine a drop of blood (high power). Observe — and draw 



(1) The oval nucleated yellowish-red corpuscles which, when seen on 



edge, have a flattened appearance. 



(2) The granular amoeboid colourless corpuscles which are few in number 



and often provided with two or more nuclei. 

 (&) Cut out the heart leaving portions of the large vessels attached, and 

 examine it in a watch-glass filled with spirit. Observe the divisions ; 

 sinus venosus, atrium, ventricle, and truncus arteriosus. 



(1) Open the atrium and observe the septum dividing it into two 



chambers ; notice the opening of the sinus venosus to the right 

 of the septum, into the large right auricle and the opening of the 

 united pulmonary veins to the left of the septum into the small left 

 auricle. 



(2) Open the truncus arteriosus longitudinally, and observe the longi- 



tudinal valve which separates the left passage leading to the opening 

 into the pulmo-cutaneous arches, from the right leading to the carotid 

 and systemic arches. Observe also the semilunar valves which 

 separate the synangium from the pylangium and the pylangium from 

 the ventricle. 



(3) Cut across the ventricle and notice ihe small cavity and the thick 



spongy walls, 

 (c) Make a sketch (6 nat. size) showing the cavities of the heart and truncus 

 arteriosus, and the various valves. 



11. The Larynx and Lungs. 



Expose the hyoid apparatus by removing the muscles attached to its under 

 surface, introduce a probe through the glottis into the right lung, remove 

 the ventral wall of the laryngeal chamber, and slit up the right lung along 

 the probe with a pair of scissors. 



Examine and sketch (2 nat. size) — the lower jaw to be included in the sketch — 



(a) The hyoid indicating the body and the anterior and posterior cornua. 



(b) The larynx showing the arytenoid and laryngo-tracheal cartilages, and 



the vocal cords stretching across the small laryngeal chamber. 



(c) The lungs indicating the sacculated cavity of the right lung in direct 



communication with the air chamber. 



12. The Alimentary Canal. 



(a) Observe the wide oesophagus ; the tubular stomach distinctly separated 



from the duodenum by the pyloric constriction, the gall bladder lying 

 between the divided left lobe and the smaller entire right lobe of the 

 liver, the bile duct entering the duodenum, the pancreas sending 

 numerous ducts into the bile duct, the spleen attached to the 

 mesentery, the small and large intestine, and the cloaca. 



(b) Cut across the oesophagus, immediately behind the posterior cornua 



of the hyoid and the large intestine at its junction with the cloaca, 

 and then remove the whole length of the alimentary canal, taking 

 with it the lungs, liver, pancreas, and spleen, but leaving the dorsal 

 aorta and kidneys. Uncoil the intestine and make a drawing show- 

 ing all the structures removed. 



(c) Slit open the alimentary canal, and note the longitudinal folds of the 



stomach, the pyloric valve, the transverse folds of the duodenum, and 

 the opening of the common bile duct. 



